docs: def errch(marker, string):
      """
      Substitute a character string for the first occurrence of
      a marker in the current long error message.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/errch_c.html
  
      :param marker: A substring of the error message to be replaced.
      :type marker: str
      :param string: The character string to substitute for marker.
      :type string: str
      """
      marker = stypes.stringToCharP(marker)
      string = stypes.stringToCharP(string)
      libspice.errch_c(marker, string)